Starter bolt snapping on Chevy 3500 truck

Guys,

I got this email today:

"We are having difficulties with a fixing a starter to this truck. Evidently, the holes that receive the starter bolts are too wide to hold the bolts so they are snapping. Over the years with bolts breaking off and drilling them out, the holes have become too wide, no longer flush. The truck mechanic, Barry,suggest that we should get a new block. All starter bolts for these trucks go directly into the engine block."

Is there another solution to replacing the block when this happens?

 

Helicoils or tack weld it on, depending on the age of the vehicle.......

I don't understand the bore spacing issue though unless it wasthe wrong unit they were trying to mount..

Obligitory Fcar content: I use an LT1, to fetch my 308GTB parts!

Strange problem, but a short block fixes everything!

 

Don't make me tell the old joke about "double bushing down...."

 

If this is the type like the old ones, the bolts go vertically up through the starter? If so, why not just drill the holes in the starter out a bit to gain some clearance? But I also dont understand why they would snap off later, after being in place for a while. If they are so offset to begin with, how do you ever screw them in in the first place? Maybe drop down to a grade 5 (or 8.8 if its metric) softer bolt. It might not snap if the bolt can give a little bit.

 

Barry needs to think outside the "block" - hehe . Here's what you can do. Get some JB weld (it's like glue; sold at most all auto parts stores, etc.) and find long studs and/or bolts and then cut the heads off. Mix up the JB Weld and put it generously it on the threads of the studs - then thread everything into the holes. Let it dry for 24 to 48 hours. Then just install the starter and use lock nuts (or nuts and lock washers) on the end of the studs. That should work fine as long as there is enough clearance to get the starter on over the studs.

One time on a race motor, a stud for the exhaust manifold snapped off. I drilled it out, but the drill slipped off and went right into the aluminum head ($$$ repair). I ended up using a thread insert and some JB Weld. I wasn't sure if it would hold, due to the torque and also the high heat, but I never had any problems with it through the life of the motor.

If changing the starter over to using studs will not work, you may be able to find a thread insert that will install in the holes. It's sort of like a threaded plug that reduces the hole back to the original size. Generally what you do is drill out the hole, retap it, then insert the thread insert, which reduces the thread size back down to the original hole size (I always install them with some JB Weld or Red thread lock). Here is the company I use - they have been around for ages and are very good:

http://www.timesert.com/

The other thing you could do is to insert the bolts and just tack weld them with a MIG welder. But JB Weld should accomplish the same thing.

If the starter position will not allow you to use the stud method, then you could also try this: clean the existing holes out, then fill both holes completely full with JB Weld. Give it 2 or 3 days to set up, then drill and tap the holes back to the original size. JB Weld is so tough that you can mill/drill/tap it, etc. Then just be careful not to over torque the bolts (also use anti-seize when you install them, so you get a nice even torque).

Using a timesert would probably be my first choice. Changing to studs and using some JB weld to hold everything solid would be my second choice. If those two options don't work, then fill the holes with JB weld and re-tap. Rebuilding the motor on a new block just because some threads pulled out is silly.

Hope that helps.

Ray

 

Do Chevys still have starter bolts that are knurled to a larger diameter? They used to be "knurled-up" to act as a dowel pin to locate the starter.

Are the bolts that are breaking from a Chevy dealer or from a hardware store? On the older cars they were pretty heavy duty bolts with about an inch of heavy knurling just on top of the threads.

Mark

 

1) Go up one diameter size. (& consider metric)
2) Drill out both sets of holes to match.
3) Use hardenened grade bolts.

 

Is'nt there a chevychat.com?

 

The problem with that is that the starter has a long snout that needs to be inserted into the bellhousing thus a stud will not work in this instance. I would suggest the timesert over a heli-coil. Other than that a block replacement would be your best bet. In all my years I have never seen a starter bolt shear off but I work at a Chrysler dealer and then a broken bolt is the least of my worries if you know what I mean.

 

I second what mike said above about using the timesert over the heli-coil. Timeserts are very good. I would suggest installing them with JB weld however, so there is some added support in there. I have cracked timeserts in the past when torquing things down again and the addition of JB weld seems to help keep that from happening.

Ray

 

guys thanks for the advice,

I have passed it along..... we'll see what happens

 

Shim the starter correctly, and there wont be a problem.

Mechanical clown. A 3/8 grade 5 bolt is 120,000 pounds tensile strength.

http://widget.ecn.purdue.edu/~me452/homeworks/hw%2011%20bolt%20geom%20and%20k/hw11sol.Spring06.doc

Use ARP grade 8 studs, or even one if you have to, use just one stud.

 

Is there an additional bracket that goes on the other end of the starter that may be missing on this particular truck?

 

Good catch. All Chevys have a bracket, that often gets left off by the same mechanics who don't shim the starter.

 

Probably not with the gearheads we have here! LOL!

LetJet is a Team Zupra sponsor, so we are all helping out!

 

Thanks guys,

BTW - if there is chevychat, and I'm sure there is.... I don't know anyone to help me there.

So, it's my "crew" here that I thought could come through for me.

All info has been sent and I think we're good.